~ the panther occurs in both species, the jaguar
(Panthera onca) and the leopard (Panthera
pardus). It is difficult to decide, whether the "panther"
was a leopard or a jaguar. Differences are to be recognized best
by the statue. The jaguar is built more strongly. They can also
be well ditiguished by their head. But the easiest way is to
see them in their typical habitat. The jaguar lives in South
America and you will find the leopard in Africa and Asia. ;-)

How do they get their black fur?

~ it is hereditary with jaguars dominant. Depending on
situation of light the "panther" appears completely black or
it draws for marks of the coat off. (except when you will
meet it in the night. *gg*)

~ the black coloration of the leopards is passed on rezessiv,
also called "melanism(?)". The typical coat pattern becomes
visible under bright light.

"Basically, the fur color is determined by pigment cells
(Melanocyten) which lay beneath the skin. They produce so
called melanine, which is transported to the hair. There
are two kinds: Eumelanine, which turns the hair brown to
black and Phaeomelanine, which causes a reddish color.
Animals that suffer melanism produce more melanine, but
if you look hard, you'll recognize the typical pattern." (Link:
Why are jaguares spotted and tigers striped)

This picture is a good excample
how the panther looks with sufficiant light.

~ rumor has it, that the black ones are agressive. But it is
also said, that their behavior does not differ from that of
normal jaguars/leopards. (But who knows, what science will
uncover in the future?)